Internal combustion engines have been around for many years for converting the energy of combusted gases into mechanical work in the form of a rotating crankshaft. One type of internal combustion engine known in the art is the reciprocating piston internal combustion engine. The conventional reciprocating piston internal combustion engine typically includes a housing, generally referred to as a block, that defines a plurality of cylinders arranged either in an in-line, V-type, or boxer configuration. Journaled at the lower end of the cylinders is a crankshaft. Each cylinder houses a piston reciprocally driven by the crankshaft via respective connecting rods. The cylinders and the pistons cooperate to form working chambers for the induction, compression, combustion, and exhaustion of air/fuel mixtures. The engine further includes pairs of camshafts, which are operatively connected to the crankshaft through a chain drive or other transmission so that they are driven to rotate in synchronization with the rotation of the crankshaft.
The top of each cylinder includes intake ports and exhaust ports. The intake and exhaust ports are opened and closed via respective valves. The valves are reciprocally mounted within the housing and are actuated via camshafts. The camshafts are operably connected to each valve via rocker arms pivotally mounted within cylinder heads mounted to the engine block. The valves are normally biased via springs to seal the intake and exhaust ports in a closed position. The springs are also operable to keep constant engagement between the top of each valve and a pivoting portion of the respective rocker arm.
While this particular configuration of an internal combustion engine works reasonably well to convert the energy of combusted gas into rotational mechanical work, it has many deficiencies due to its inherent design. First, these engines typically need to have large displacements to produce a desired amount of work. This typically requires the physical dimensions of the engine block to be quite large which causes problems in space sensitive applications. Additionally, based on the offset angle of the connecting rods, and the configuration of the crankshaft, cams, and springs, the reciprocating piston engine is not very efficient in converting reciprocating motion of the pistons into crankshaft rotation. Further, these engines require an exorbitant amount of parts, which increases costs, and decreases reliability.